The present invention relates to a knockdown hand tool structure in which by means of V-shaped annular engaging grooves of the screwdriver stem, the projecting length thereof can be changed for application to various holes with different depths and diameters so as to tighten or untighten a screw or a nut. The use and replacement of the screwdriver stem are facilitated and quickened and the cost for additional screwdriver stem is saved. Also, the occupied room is reduced to facilitate carriage of the hand tool.
FIG. 1 shows a conventional hand tool including a grip 10 and a socket 50. The grip 10 is connected with a stem 11 forward projecting from the center of the front end face of the grip 10 by a certain length. The front end section of the stem 11 is formed with a rectangular fitting section 12. A steel ball 13 is inlaid in one side of the fitting section 12. The rear end of the socket 50 is formed with a rectangular fitting hole 51. The front end of the socket 50 is formed with a polygonal tool socket 52.
When assembled, as shown in FIG. 2, the fitting section 12 of the grip 10 is fitted into the fitting hole 51 of the socket 50 with the steel ball 13 engaged with the socket 50 so as to fix the socket 50 with the grip 10. When replacing the socket 50 with another with different specification, the socket 50 is directly drawn outward and separated from the grip 10.
The above conventional hand tool has some shortcomings as follows:
1. The fitting section 12 of the grip 10 can be only fitted with the socket 50 and cannot be co-used with different screwdriver stems with various specifications or types of screwdriver heads. Therefore, the application range is narrower.
2. The stem 11 of the grip 10 is not adjustable in length. Therefore, in use, it is necessary to replace the grip 10 with different length of stem 11 in accordance with the requirement of application situation. This is troublesome and inconvenient. Also, it is necessary to purchase various kinds of grips 10 and the cost is increased.
FIG. 3 shows another type of conventional hand tool including a grip 20, a screwdriver stem 30, a fitting stem 40 and a socket 50. The grip 20 is connected with a hexagonal stem 21 forward projecting from the center of the front end face of the grip 20 by a certain length. The front end section of the stem 21 is connected with an enlarged fitting head 22. The front end of the fitting head 22 is formed with a central hexagonal fitting hole 23. A steel ball 24 is inlaid in one side of the fitting hole 23. The screwdriver stem 30 is a hexagonal stem body. The front end of the screwdriver stem 30 is formed with a cross-shaped screwdriver head 31. (The screwdriver head 31 can be otherwise shaped.) The fitting stem 40 is a hexagonal stem body having a rectangular fitting section 41 at front end. A steel ball 42 is inlaid in one side of the fitting section 41. The rear end of the socket 50 is formed with a rectangular fitting hole 51. The front end of the socket 50 is formed with a polygonal tool socket 52.
When assembled, as shown in FIG. 4, the rear section of the screwdriver stem 30 is inserted into the fitting hole 23 of the fitting head 22 of the grip 20. By means of the steel ball 24 in the fitting hole 23, the screwdriver stem 30 is fixedly engaged with the grip 20 for use of the screwdriver stem 30. When applied to a nut, as shown in FIG. 5, the screwdriver stem 30 is first extracted from the fitting hole 23. Then the rear section of the fitting stem 40 is inserted into the fitting hole 23 of the fitting head 22 of the grip 20. By means of the steel ball 24 in the fitting hole 23, the fitting stem 40 is fixedly engaged with the grip 20. Then the fitting section 41 of the fitting stem 40 is fitted into the fitting hole 21 of rear end of the socket 50. By means of the steel ball 42 of the fitting section 41, the fitting stem 40 is fixedly engaged with the socket 50 for use of the socket 50.
The above conventional hand tool has some shortcomings as follows:
1. The fitting head 22 of the stem 21 of the grip 20 is enlarged. In the case that the screwdriver stem 30 is used to tighten a screw into a narrower hole with smaller inner diameter, the fitting head 22 may be stopped by the outer edge of the hole to make the screwdriver stem 30 impossible to extend to the screw.
2. When it is desired to further use the screwdriver stem 30 after using the socket 50, it is necessary to extract the fitting stem 40 and the socket 50 and then again insert the rear section of the screwdriver stem 30 into the fitting hole 23 of the fitting head 22 of the grip 20. Such procedure is troublesome and time-consuming.
3. The stem 21 of the grip 20 has fixed length which cannot be adjusted. Therefore, in use, it is necessary to replace the screwdriver stem 30 or fitting stem 40 with one with different length or specification or pattern in accordance with the requirement of application situation. This is troublesome and inconvenient. Also, it is necessary to purchase various kinds of screwdriver stems 30 and fitting stems 40 so that the cost is increased.
It is therefore a primary object of the present invention to provide a knockdown hand tool structure in which in the case that a screw is tightened in a narrower hole, the body of the screwdriver stem is slender and has unified diameter so that the screwdriver stem can easily extend into the narrower hole to drive the screw.
It is a further object of the present invention to provide the above knockdown hand tool structure in which the fitting post and the socket are fitted on the screwdriver head of the screwdriver stem. In the case that it is desired to further use the screwdriver stem after using the socket, a user only needs to extract the fitting post and the socket and then the screwdriver stem can be directly used. Therefore, it is no more necessary to extract the socket and then insert the screwdriver stem and the replacement is facilitated and quickened.
It is a further object of the present invention to provide the above knockdown hand tool structure in which in use, the screwdriver stem can be directly inward or outward moved to change the length thereof as necessary. Alternatively, the screwdriver stem can be extracted and turned over to use the other screwdriver head with different specification or pattern. Therefore, the use is facilitated and it is unnecessary to purchase additional screwdriver stem so that the cost is saved and the occupied space is reduced to facilitate carriage of the hand tool.
The present invention can be best understood through the following description and accompanying drawings wherein: